MOSFET phototransistors, methods of operating the MOSFET phototransistors and methods of making the MOSFET phototransistors are provided. The phototransistors have a buried electrode configuration, which makes it possible to irradiate the entire surface areas of the radiation-receiving surfaces of the phototransistors.

A method (200) for fabricating thin-film optoelectronic devices (100), the method comprising: providing a substrate (110), forming a back-contact layer (120); forming at least one absorber layer (130) made of an ABC chalcogenide material, adding at least one alkali metal (235), and forming at least one cavity (236, 610, 612, 613) at the surface of the absorber layer wherein forming of said at least one cavity is by dissolving away from said surface of the absorber layer at least one crystal aggregate comprising at least one alkali crystal comprising at least one alkali metal. The method (200) is advantageous for more environmentally-friendly production of photovoltaic devices (100) on flexible substrates with high photovoltaic conversion efficiency and faster production rate.

A method for forming a back contact on an absorber layer in a photovoltaic device includes forming a two dimensional material on a first substrate. An absorber layer including CuZnSnS(Se) (CZTSSe) is grown over the first substrate on the two dimensional material. A buffer layer is grown on the absorber layer on a side opposite the two dimensional material. The absorber layer is exfoliated from the two dimensional material to remove the first substrate from a backside of the absorber layer opposite the buffer layer. A back contact is deposited on the absorber layer.

A method for forming a back contact on an absorber layer in a photovoltaic device includes forming a two dimensional material on a first substrate. An absorber layer including CuZnSnS(Se) (CZTSSe) is grown over the first substrate on the two dimensional material. A buffer layer is grown on the absorber layer on a side opposite the two dimensional material. The absorber layer is exfoliated from the two dimensional material to remove the first substrate from a backside of the absorber layer opposite the buffer layer. A back contact is deposited on the absorber layer.

MOSFET phototransistors, methods of operating the MOSFET phototransistors and methods of making the MOSFET phototransistors are provided. The phototransistors have a buried electrode configuration, which makes it possible to irradiate the entire surface areas of the radiation-receiving surfaces of the phototransistors.

Disclosed is a polyimide precursor composition for the production of a flexible board of a photoelectronic device. The polyimide precursor composition includes a polyimide precursor derived from a diamine or acid dianhydride including a structure of Formula 1:

##STR00001##

wherein R.sub.1 to R.sub.8, m1, m2, and m3 are as defined in the specification. Also disclosed is a polyimide film produced from the polyimide precursor composition. The polyimide film is obtained by applying the precursor composition to a substrate and curing the composition. The polyimide film has high transparency and good heat resistance. In addition, the polyimide film exhibits good dimensional stability because the substrate does not undergo an increase in stress even during high-temperature heat treatment.

The present invention relates to a multilayer structure including a base (X) and a layer (Y) stacked on the base (X), the layer (Y) containing the following at a specific ratio: a metal oxide (A); a phosphorus compound (B) containing a moiety capable of reacting with the metal oxide (A); and cations (Z) with an ionic charge (F.sub.Z) of 1 or more and 3 or less.

An apparatus including a flexible substrate; and an overhanging electronic component island, the electronic component island configured to be less flexible than the flexible substrate and including one or more electronic components, wherein the electronic component island includes a substrate-face with a connection portion and an overhang portion, the connection portion being mechanically coupled to a surface of the flexible substrate via a single connection-support pad and the overhang portion configured to overhang and be substantially free of the underlying flexible substrate such that the underlying flexible substrate can be strained independently from the overhang portion under operational strains of the flexible substrate.

There is disclosed a method of preparing a photovoltaic device. In particular, the method comprises making thin-film GaAs solar cells integrated with low-cost, thermoformed, lightweight and wide acceptance angle mini-CPCs. The fabrication combines ND-ELO thin film cells that are cold-welded to a foil substrate, and subsequently attached to the CPCs in an adhesive-free transfer printing process. There is also disclosed an improved photovoltaic device made by the disclosed method. The improved photovoltaic device comprises a thin-film solar integrated with non-tracking mini-compound parabolic concentrators, wherein the plastic compound parabolic concentrator comprise two parabolas tilted at an angle equal to the acceptance angle of the compound parabolic concentrator.

A method of bonding solar cell component to a support and the solar cell assembly thus obtained. The method of bonding solar cell component to a support comprises: disposing metallized traces on the support; dispensing bonding adhesive on front of the support or on back of the solar cell component; and laying down the solar cell component on the support and soldering the solar cell component to the metallized traces on the support. The support is a glass support with integrated circuits.